Cam grinding apparatus



Jan; 28, 1947. c. J. GREEN 2,415,062

CAM GRINDING APPARATUS Filed Jan. 24, 1946 f 4 Sheets-Sheet 1 CLARENCE J. GREEN Jan. 28, 1947. c, GREEN 2,415,062

CAM GRINDING APPARATUS Filed Jan. 24, 1946 4 Sheets-Sheet 2 Jan. 28, 1947. I c, GREEN 2,415,062

CAM GRINDING APPARATUS Filed Jan. 24, 1946 4 Sheets-Sheet 3 CLARENCE J. GREEN Jan. 28, 1947. c GREEN 2,415,062

CAM GRINDING APPARATUS Filed Jan. 24, 1946 4 Sheets-Sheet 4 CLARENCE J. GREEN Patented Jan. 28 1947 I 2,415,0 2 v CAM GRINDING APPARATUS Clarence J. Green, Worcester, Mass., assignor to V Norton Company, Worcester, Mass a corporation of Massachusetts Application'January 24, 1946, Serial N0..643,011

This invention relates to grinding machines, and more particularly to a machine for grinding automotive cams and the like.

One object of the invention is a simple and thoroughly practical cam grinding apparatus for grinding cam shapes and other irregular noncylindrical work pieces. Another object of the invention is to provide a cam grinding machine with a rock bar which is given a secondary motion so that the line of grinding contact between the cam being ground and the grinding wheel al- I mounted rock bar and to provide a plurality of master cams synchronously to rock the rock bar 7 and swing the frame so as to grind a predetermined contour on the cam being ground while maintaining the line of grinding contact always in the same position.

A further object of the invention is to provide a cam grinding apparatus having a .pivotally mounted rock bar supported on a pivotally mounted frame and a plurality of master cams for controlling the movement of the rock bar and the frame to grind a cam to the predetermined size and contour so that the contour of the cam being ground will remain constant regardless of reduction in diameter of the grinding wheel due to wheel wear or truing. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements,

.relationship of the cam being ground to the grinding wheel;

6 Claims. (01. 51-101) 2 Fig. 5 is a view similar to Fig. 3, but with the cams and parts in different positions;

Fig. 6 is a fragmentary vertical sectional view, on an enlarged scale, taken approximately on the line 6-6 of Fig. 4;

Fig. 7 is a fragmentary sectional view, taken approximately on the line 'I'| of Fig. 2; and

Fig. 8 is a fragmentary perspective view, showing the relationship of rock bar, pivotally supported frame, grinding wheel and associated parts.

A grinding machine has been illustrated in the drawings comprising a base H) which serves as a support for a longitudinally movable work supporting table II. The table II is slidably supported-on a V-way l2 and a flat way l3 formed on the base Ill.

The work table I I may be moved longitudinally relative to the base Ill to position a work piece supported thereon for a grinding operation either by a power operated mechanism such .as is old and well known in the art or by means of a manually operable traverse mechanism. As illustrated in the drawings, a manually operable traversemechanism has been illustrated comprising a manually operable rotatable traverse wheel l5 which is operatively connected torotate a gear IS. The gear I6 is mounted on a rotatable shaft l'lwhich is Journalled in suitable bearings (not shown) in the base Ill. The shaft II also supports a gear [8 which meshes with a rack bar 19 depending from the underside of the table A rotatable grinding wheel 20 is supported on a rotatable wheel spindle,(not shown) which is mounted in suitable bearings in a transversely movable wheel' slide 2|. The wheel slide 2| is arranged to slide transversely relative to the base III on a V-way 2.2 and a flat way 23 formed on the base Ill. The grinding wheel 20 is pref- .erably rotated bymeans of an electric motor 24 x which is mounted on the upper surface of the Fig. 4 is a fragmentary sectional view, on an enlarged scale, showing the rock bar and the pivotally mounted frame together with the master cams and followers;

the grinding wheel 20 relative to a work piece being ground and to feed the grinding wheel 20 into the work to grind it to the desired and predetermined size. This wheel feeding mechanism has not been illustrated in detail, since it is not considered to be a part of the present invention. The wheel feeding mechanism is substantially identical with that which is old and well known in the grinding art such as, for example, that shown in the expired U. S. patent to C. H. Norton No. 762,838 dated June 14, 1904, to which reference may be had for details of disclosure not contained herein. The wheel feeding mechanism may comprise a manually operable rotatable feed wheel 29 which is provided with the usual micrometer feed adjusting mechanism 30. The feed wheel 29 is operatively connected through a gear mechanism (not shown) to rotate a gear 3| which is mounted on the outer end of a rotatable cross feed' screw 32. The feed screw 32 is arranged to mesh with a half nut 33 depending from the underside to the wheel slide 2 I. It will be readily apparent from the foregoing disclosure that a rotary movement of the feed wheel 29 will be imparted to rotate the feed screw 32 and through the half nut 33 to cause a transverse movement of the wheel slide 2| and the grinding wheel 20. The direction of rotation of the feed wheel 29 will determine the direction of movement of the wheel slide 2|.

In order to attain one of the main objects of the invention, a. work supporting and rotating mechanism is provided whereby a work piece may be moved so as to generate a predetermined contour on the work piece and also moved so as to maintain the line of grinding contact between the cam being ground and the grinding wheel in the same position. for example, in a horizontal plane passing through the grinding wheel axis so that a predetermined contour will be generated regardless of the diameter of the wheel being used. By providing such a mechanism the contour of the cam being ground will remain constant regardless of reduction in diameter of the wheel due to wheel wear or truing operations.

A diagrammatic illustration in Fig. 3 shows the relationship between the grinding wheel 20 and the cam 53 to be ground. When the cam 53 is rotated in a clockwise direction as indicated by the arrow, the line of grinding contact remains in a horizontal plane passing through the wheel axis as indicated by the line X-Y while the surface of the cam A-D is being around. When the cam rotates from B to C, it is necessary to raise the axis of rotation of the cam 53 in order to maintain the line of grinding contact in plane X-Y. Similarly in grinding from B to A, it is necessary to again lower the axis of rotation of the cam 53 in order to maintain the line of grinding contact in the plane X-Y.

As shown in the drawings, the work supporting and rotating mechanism may comprise a pivotally mounted frame 38 which is provided at its opposite ends with trunnion studs 39 and 40 (Fig. 8). The trunnion studs 39 and 40 are supported in bearing brackets 4| and 42 which are either fixedly mounted or formed integrally with thetable II, The rock bar 43 is pivotally supported on the frame 38 by means of trunnion studs 44 and 45.

The rock bar 43 is provided with a rotatable work support comprising a head stock spindle or master cam spindle 46 which is journalled in brackets 41 and 48. The brackets 41 and 48 are either formed integrally with or fixedly mounted on the rock bar 43. The spindle 46 is provided with a work center 49 which serves as a support for the left hand end of a work piece.

A footstock 50 (Fig. 1) is adjustably mounted on the rock bar 43. The footstock' 50 is provided with a footstock center 5| which serves as a support for the right hand end of a cam shaft 52 having a cam 53 to beground.

The master cam spindle 46 is provided with a master cam 55 which engages a rotatable follower roller 56. The follower roller 56 is rotatably supported on a shaft 51. The master cam 55 and follower roller 56 serve during rotation of the spindle 46 to rock the rock bar 43 so as to transmit a corresponding motion to the cam 53 being ground and thereby to generate the desired and predetermined contour thereon. It will be readily apparent that by providing a master cam 55 of the desired shape a cam being ground may be precisely generated to the desired and predetermined contour.

In order to maintain the line of grinding contact between the cam being ground and the grinding wheel in a predetermined position, it is desirable to impart a secondary movement to the rock bar 43, The rock bar 43 is arranged so that it may be moved bodily in substantially vertical direction so as to raise and lower the axis of the spindle 46 and also the axis of the cam 53 being ground to maintain the line of grinding contact in a predetermined position. This is preferably accomplished by providing a second master cam 58 on the master cam spindle 46. A follower roller 59 is rotatably supported on a stud 60. The stud 60 is supported by means of a bracket 64 which is adjustably mounted within a housing 63 on the work table II. The follower roller 59 is preferably arranged with its axis in a vertical plane passing through the axis of the spindle 46 and the axis of movement of the rock bar 43 so that motion of the master cam 58 as it rotates will move the rock bar 43 bodily in a substantially vertical plane. The follower roller 56 and shaft 51 are preferably supported in a bracket 62 which is fixedly mounted within the housing 63. It will be readily apparent from the foregoing disclosure that by providing a master cam 58 of the predetermined shape which of course is coordinated with the shape of the master cam 55 the work axis may be shifted during thegrinding operation so as to maintain the line of grinding contact in a predetermined plane.

In'order to maintain the master cam 55 in operative engagement with the follower roller 56, during rotation of the master cam spindle 46, a yieldable mechanism is provided. An upwardly extending arm 65 is fixedly mounted on the rock bar 43 and carries at its upper end a stud 66. The stud 66 serves as a, support for one end of a tension spring 61. The other end of the spring 61 is supported by a stud 68. The stud 68 is preferably supported by the housing I2 and is. provided with a threaded portion and adjusting and lock nuts 69 whereby the tension of the spring 61 may be varied as desired so that the master cam 55 may be maintained in engagement with the follower roller 56 with the desired pressure.

A driving mechanism is provided for rotating the master cam spindle 46 and the cam shaft 52. This mechanism preferably comprises an electric motor 15 mounted on the upper surface of the housing 63. The motor 15 is provided with an armature shaft 16 having a multiple V-groove pulley 11 mounted on the right hand end thereof. The pulley I1 is connected by means of multiple V-belts I8 with a multiple V-groove pulley 19, The pulley I9 is mounted on the left hand end of a rotatable shaft 80 which is in turn journalled in a suitable bearing within the bracket 8 I. A universal driving connection is preferably provided to connect the shaft 80 with the master cam spindle 86. In the preferred form, a universal joint 82 is mounted on the right hand end of the spindle 80. The universal joint 82 is connected by means of a telescopic shaft 83 with a universal joint 84 which is operatively connected with the left hand end of the master cam spindle 46. It will be readily apparent from the foregoing disclosure that rotary motion of the motor will be imparted through the mechanism above described to rotate the master cam spindle 46. Rotation of the master cam spindle 46 and the master cams 55 and 58 respectively will impart a combined rocking movement to the rock bar 43 and the frame 38 respectively so as to generate a predetermined contour on the cam 53 and at the same time to maintain the line of grinding contact in' a predetermined position.

The operation of this improved cam grinding machine will be readily apparent from the foregoing disclosure. A pair of master cams 55 and 58 of the desired and predetermined shape are.

v ment to said bar to generate a predetermined mounted on the master camspindle 46. A work tive rotary motion to the master cam spindle 4B to generate a predetermined contour on the cam;53 being ground. During rotation of the master cam spindle 46 and the cam shaft 52, the grinding wheel 20 may be fed transversely toward the cam 53 being ground so as to grind the cam .the

contour on a cam being ground, and means to move said rock bar bodily in synchronism with the rocking movement of said bar so as to maintain the line of grinding contact between the grinding wheel and cam being ground in a predetermined plane passing through the grinding wheel axis.

4. In a cam grinding machine having a base, a transversely movable rotatable grinding wheel and a longitudinally reciprocable work table, a frame movably mounted on side table, a rock bar pivotally mounted on said frame, a rotatably work support on said rock bar including a rotatable spindle and a footstock to support a cam to be ground, means to rotate said spindle, a master cam on said spindle and a follower roller to impart a rocking movement to said rock bar relative to said frame and cam being ground to grind apredetermined contour thereon, and means to move said frame in synchronism with the rocknot only to a predetermined contour but also to.-

a predetermined size. i

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is tobe understood that all matter hereinbefore set'forth, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a cam grinding machine having a rotatable grinding wheel and a work table, a rock bar, a work support including a rotatable spindle on said rock bar, means to rotate said spindle, means including a master cam on said spindle and a follower roller to impart a rocking movement to said bar to generate a predetermined contour on a cam being ground, and means to impart a secondary movement to said rock bar so as to shift the axis of the cam being ground to maintain a predetermined line of contact betweenthe grinding wheel and cam being ground.

2. Ina cam grinding machine having a rotatable grinding wheel and a work table. a rock bar, a work support including a rotatable spindle on said rock bar, means to rotate said spindle, means including a'master cam on said spindle and a follower roller to impart a rocking movement to said bar-to generate a predetermined contour on a cam being ground, and means to impart a substantially vertical movement to said rock bar to ing movement of said rock bar so as to maintain the line of grinding contact between the wheel and cam being ground in a predetermined posi- 5. ,In a. cam grinding machine having a base, a transversely movable rotatable grinding wheel and a longitudinally reciprocable work table, a

frame pivotally mounted on said table, a rock bar pivotally mounted on said frame, a rotatable work support on saidrock bar including a rotatable spindle and a footstock to support a cam to be ground, means to rotate said spindle, a master cam on said spindle and a follower roller to impart a rocking movement to said rock bar and cam being ground to grind a predetermined contour thereon, and means including a cam and a follower t impart a rocking movement to said frame so as to maintain the line of grinding contact between the grinding wheel and the cam being ground in a predetermined plane passing through the grinding wheel axis.

6. In a cam grinding machine having a base, a transversely movable rotatable grinding wheel and a longitudinally reciprocalble work table, a frame pivotally mounted on said table, a rock bar pivotally mounted on said frame, a rotatable work support on said rock bar including a rotatable spindle and a footstock to support a cam to be ground, means to rotate said spindle, a master cam onsaid spindle and a follower roller to impart a rocking movement to said rock bar relative to said frame to grind a predetermined contour on 

